Effect of 24 h capsaicin (15 mg/kg, s.c.) or its vehicle on B
R mRNA expression levels in cervical (C2), thoracic (T4) and lumbar (L5) segments of rat spinal cord. Data represent the means ± S.E.M. of 4 rats per group. Comparison with vehicle (*) or lumbar segment (+) is indicated by +,* P < 0.05; ** P < 0.01.